Alrighty here goes from what I read during the lessons
A sarcomere a sub-unit of a muscle cell which comprises of various regions/bands.A sarcomere is made up of Myosin along with Actin filaments.
Distance between two Z-line is a sarcomere a dark band.Other regions are: Band M,H,I and A.
Z-Line is where the actin filaments are attached to.
Band I- Made up of actin filaments only!
Band H:Myosin only
Band A: Made of both myosin and actin filament.
When a sarcomere contracts : Z- disc distance decreases along I and increase in A.

Argh.... **** it! cant multitask I need to take some rest or something sorry Its just that I am having mental block now... :/ be back later...

Heres the first installment of the revision cards all you guys have been msging me about :P, I started with the hardest topic for me which was the Cloning+Biotechnology. I did them all in one day so i might have missed something out, Please tell me if I have

Heres the first installment of the revision cards all you guys have been msging me about :P, I started with the hardest topic for me which was the Cloning+Biotechnology. I did them all in one day so i might have missed something out, Please tell me if I have

Micro-organisms are used becaaause:
-They grow quickly/rapidly under the right conditions
-The optimum growing conditions can easily be reproduced
-They can grow in anywhere in the world as they are not dependent on climate
-Can be grown on waste/toxic/useless nutrient material (so thats inexpensive too)
-The products produced are usually purer than those made by chemical processes
-Reduce the temperature that reactions need to take place at (thats mainly enzymes so reduce costs).

Alright, you can have...explain how mutations can be beneficial/harmful or neutral.

I find myself falling slightly short of detail in genetic engineering -.-

(Original post by tgr141291)
What Past Papers From The Old Spec Can We Do Please

the applications of genetics are quite good for the meiosis and gene technology sections, but you have to pick through them a bit because there is some stuff about seed banks which i dont think we need to know

also the central concepts are good, but again only about half of each paper is relevant to unit 5, some of it is unit 5 revision stuff though so if you want to practice your synopsis questions!

(Original post by Falcon91)
Micro-organisms are used becaaause:
-They grow quickly/rapidly under the right conditions
-The optimum growing conditions can easily be reproduced
-They can grow in anywhere in the world as they are not dependent on climate
-Can be grown on waste/toxic/useless nutrient material (so thats inexpensive too)
-The products produced are usually purer than those made by chemical processes
-Reduce the temperature that reactions need to take place at (thats mainly enzymes so reduce costs).

Alright, you can have...explain how mutations can be beneficial/harmful or neutral.

I find myself falling slightly short of detail in genetic engineering -.-

Mutations are classified as being neutral when they have an effect that is neither advantageous or disadvanatgeous, or the mutation has occured on a non-coding region of DNA so has no effect, or it is a silent mutation, where the nucleotide base that is substituted results in a triplet code for the same amino acid so the primary structure and therefore tertirary sturcture of the polypeptide is unaltered.
Examples of neutral mutations are things such as being able to roll your toungue, being able to smell honeysuckle etc.

Mutations are harmful when the effect is disadavantageous. For example with cystic fibrosis, this arises due to a mutation that affects the transmembrane chloride channels, and as a result the transport of chloride ions and water across various membranes is disrupted. This leads to a build up of mucus in airways and reproductive tracts, leading to further infections and infertitility.

Mutations are beneficial when the effect is advantageous, for example a mutation that alters the colour of the coat of an animal to make it more camoflaged to its surroudnings. It is more likely to survive an pass on its faourable alleles.

There are also mutations that can be harmful or benefical depending on environmental conditions.

Desribe what learned and innate behaviour is, give examples of several types of learned and innate behaviours.

Hey guys, I've got the OCR Heinemann textbook, and for the point about apical dominance they literally have got two solid walls of text which go into a lot of detail about both auxin and gibberellin - how much do you think we need to know?

I thought it was simply that auxin inhibits side shoots while promoting the apical bud, and gibberellins simply stimulate stem elongation?

(Original post by radical07)
Hey guys, I've got the OCR Heinemann textbook, and for the point about apical dominance they literally have got two solid walls of text which go into a lot of detail about both auxin and gibberellin - how much do you think we need to know?

I thought it was simply that auxin inhibits side shoots while promoting the apical bud, and gibberellins simply stimulate stem elongation?

(Original post by ViolinGirl)
Desribe what learned and innate behaviour is, give examples of several types of learned and innate behaviours.

Innate behaviour - behaviour that occurs without the need for learning (i.e. a response to a stimulus that occurs without experience).
They are rigid and inflexible, they are genetically passed on and they are the same in all members of the same species as well as being unintelligent in the sense that they have no purpose of the behaviour.

Innate behaviours are more useful for invertabrates, which have shorter lifespans, usually live without contact from others of the same species and
Examples of innate:
1) Reflexes - these help increase the chances of survival and avoid harm. An example is worms which respond to vibrations on the ground which retreat underground to avoid predation.

2) Kinesis - this is a response to a non-directional stimulus (e.g. changes in abiotic factors), one example is air humidity response shown by woodlice. They respond by increasing movement and rate of turning in order to reach more favourable conditions (woodlice turn more in areas of low humidity and turn less/stop in areas that are more humid to conserve water and avoid predators).

3) Taxis - this is a directional response to a directional stimulus (the direction of the response is determined by the direction of the stimulus). They can be +ve or -ve, an example is woodlice shown negative phototaxis to move into darker areas so that these are places that they are hidden e.g. under rocks etc, this places them in favourable conditions and avoiding predators (as a result).

Learned behaviour - behaviour that can change/adapt over an organisms life.
These vary between members of a species and can change over the organism's life. Not genetically passed on (but they can be taught). They form the basis of intelligent behaviour and have a sense of purpose.

Examples:
1 - Habituation, learning to ignore non-harmful stimuli in order to avoid wasting energy in the response. E.g. humans being able to sleep near roads by ignoring the noise of cars (else energy wasted).

2 - Operant Conditioning/trial and error learning, learning to carry out a certain response in order to obtain a reward or else a punishment is given (reinforcers), these are immediate so repetition of the behaviour wanted is learned. E.g. a mouse in a skinner box pulling a lever will keep pulling it because it will get a reward, if it pulls the wrong one it gets a shock. It will learn to pull the reward one after a period of time.

3 - Insight learning, highest form of learning as it doesnt involve simple fixed responses/action patterns. It requires logic, reasoning and judgement which forms the basis of intelligence and so uses past experience and knowledge to work out a solution to a problem. Once solution is known it is remembered, e.g. gorrilas playing with boxes previously, then learning to stack them to get to banana's which were out of reach.

"A turtle is carried by rangers in Pinta Island, northern waters of the Galapagos Archipelago, Ecuador. Under the supervision of scientists from several countries, thirty nine giant tortoises, bred in captivity at the Galapagos National Park, were taken to Pinta Island for their release as part of an effort to restore the ecological integrity of the island's ecosystems."

Desribe what learned and innate behaviour is, give examples of several types of learned and innate behaviours.

Innate behaviour is behaviour that is predetermined through genes and is not learnt, is inflexiable, is uniform thorughout a species and the organism usually has no concious awarness with regards to it.

Learnt behaviour, is behaviour that is not determined through genes but rather social and enviromental interaction, it is flexiable, it is individualistic and forms the basis of many higher order behaviours and intelligence.

Innate behaviour comes in the from of kineses, taxes, reflexes and more complex behaviour such as the wiggle dance in beas.

Reflexes, escape reflex is predetermined action to increase the chance of survival and avoid predators. Specific pattern to specific stimulus.

Kineses, increase in the rate of movement, non-directional, increases the chance of moving out of unfavourable conditions into more favourable conditions, not active.

The gene coding for insulin is made up of around 200 nucleotide bases, so for this reason it cannot be easily located within the genome consisiting of over 300 million bases. For this reasons, mRNA from the transcription of the gene is obtained, by the use of special centrifugation techniques that are carried out on pancreatic tissue. The enzyme reverse transcriptase is then used to obtain a single strand of DNA that is a copy of the gene. This is mixed with free nucleotides and DNA polymerase, the nucleotides bind with their complementary base pairs, and CDNA, the orginal gene is created.

Nucleotides are added onto the ends of this cDNA, so that complementary sticky ends are formed to that of the restriction enzyme that is used to cut up the vector (bacterial plasmids). The bacterial plasmids that have been cut and cDNA are mixed together. Some of the plasmids wil uptake the insulin gene to form recombinant plasmids while others will not, and simply reseal to form the orginal plasmids. The plasmids are then mixed with E.coli bacteria. Some of the bacteria will take up plasmids.

After this process there are 3 possibilites of cultures that can be grown. Firstly bacteria that have not uptaken any plasmid, secondly bacteria that have taken up a recombinant plasmid, and thirdly bacteria that have taken up a normal plasmid. Replica Plating is then used to identify which of the cultures is which.
The bactera with no plasmids will not grow on either ampicillin agar or tetracyline agar.
The bacteria with recombinant plasmids will grow on ampicillin agar but not on tetracyline agar. While the other bacteria will grow on both.
This allows the bacteria with recombinant plasmids to be identified. They can be cloned in large numbers, and used to synthesis insulin as part of their normal growth. This is an example of how genetic engineering can be used to generate organisms that can synthesis useful products.

Explain how speciation can occur, and decribe the different barriers that allow this to occur.